The 7 Biggest Mysteries of the Human Body

Body bogglers

If it's a good mystery you're after, look no further than the bathroom mirror. You might think scientists would have charted every aspect of their home turf by now, but they haven't. Here are seven of the biggest body bogglers.

Why so wimpy?

Photo Credit: Dreamstime

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Why so wimpy?

If you shaved a chimpanzee and took a photo of its body from the neck to the waist, "at first glance you wouldn't really notice that it isn't human," said Kevin Hunt, director of the Human Origins and Primate Evolution Lab at Indiana University. The two species' musculature is extremely similar, but somehow, pound-for-pound, chimps are between two and three times stronger than humans, Hunt told us. It's unclear why we're so much wimpier than our closest hominid relatives; perhaps our muscles' attachment points subtly differ, or our muscle fibers could be less dense.

Either way, the result is slightly humiliating. Once, in an African forest, Hunt watched an 85-pound female chimp snap branches off an aptly named ironwood tree with her fingertips. It took Hunt two hands and all the strength he could muster to snap an equally thick branch. [Chimps vs. Humans: How Are We Different?]

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On the other hand ...

On the other hand ...

Nine out of 10 people are right-handed. More mysterious than the dearth of southpaws is the fact that humans have dominant hands in the first place. Why just one hand with top-notch motor skills, instead of a double dose of dexterity? One theory holds that handedness results from having more intricate wiring on the side of the brain involved in speech (which also requires fine motor skills). Because the speech center usually sits in the left brain hemisphere — the side wired to the right side of the body — the right hand ends up dominant in most people. However, this theory gets a big blow from the fact that not all right-handed people control speech in the left hemisphere, while half of lefties do. Perplexing.

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Whose breasts?

Photo Credit: USDA

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Whose breasts?

Like all other female apes, women's breasts fill with milk when they have newborn babies to feed. But female humans alone have bloated bosoms at all other times, too. Scientists can't agree on what — or who — our "permanently enlarged breasts" are for. Most evolutionary biologists think breasts serve the purpose of attracting men, who get fooled into thinking a busty woman will make a great baby feeder (even though her breasts actually contain fat, not milk).

Hairy explanation

Photo Credit: Creative Commons | Sjef

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Author Bio

Natalie Wolchover,

Natalie Wolchover was a staff writer for Live Science from 2010 to 2012. She hold a bachelor's degree in physics from Tufts University and has studied physics at the University of California, Berkeley. Follow Natalie on Google+.